Most people assume their tap water has already been tested for anything that could affect their health. Public water systems do test and treat drinking water to meet current standards, but research is moving quickly, and scientists continue to discover potentially harmful substances that may be in drinking water before regulations are updated to address them. That gap is putting tap water under closer scrutiny.
Case in point: Earlier this year, the Environmental Protection Agency (EPA) added microplastics, pharmaceuticals, PFAS (“forever chemicals”), disinfection byproducts, and other substances to a draft drinking water watch list used to evaluate contaminants that may occur in public water supplies. Being added to the list does not mean a contaminant is harmful at the levels found in drinking water, but it does signal that regulators believe it deserves closer study.
Recent findings show why the topic feels timely across North America. The U.S. Geological Survey estimates that at least 45% of U.S. tap water may contain one or more types of PFAS, while researchers have reported microplastics in tap water, bottled water, and human tissues and organs. Canada has also moved PFAS guidance forward, with an objective for a group of PFAS in drinking water due to concerns about long-term exposure.
So what exactly could be in the water you drink, cook with, and use every day? As Culligan explains, the answer can depend on where you live, how your local water is treated, and which substances researchers and regulators are still working to understand.
Why emerging contaminants are receiving more attention
The growing attention around emerging contaminants can feel sudden, especially because many of these substances have been in use for years. What has changed is the science around them: Researchers can now detect smaller traces of chemicals and particles in water, and public agencies are taking a wider look at substances that older regulations were not built to address.
The EPA watch list captures that broader focus. According to the Federal Register notice, the draft list includes 75 chemicals, four chemical groups, and nine microbes that may occur in public drinking water and may warrant closer review. For consumers, it points to a changing regulatory landscape, where agencies are looking beyond familiar contaminants while many newer concerns are still being studied.
The contaminants scientists are watching most closely
The contaminants drawing attention are not all the same. Some come from industrial products, some from consumer goods, and some can form during water treatment. Together, they show why the conversation around water quality is widening beyond the contaminants many people already know.
PFAS
PFAS are often called forever chemicals because they break down very slowly in the environment. They have been used in products such as stain-resistant fabrics, nonstick cookware, food packaging, and firefighting foams, which have contributed to their presence in water, soil, and air. Studies have linked exposure to certain PFAS to increased risks of some cancers, reduced immune function, and developmental concerns.
Microplastics
Microplastics are tiny plastic fragments that can come from larger plastic items as they break down or from products manufactured with small plastic particles. They have been found in rivers, lakes, bottled water, and tap water, and recent reviews have reported microplastics in human tissues and organs, adding to public concern while scientists continue to investigate what widespread exposure may mean for long-term health.
Pharmaceuticals
Pharmaceuticals can enter the water cycle through human waste, agricultural runoff, and improper disposal. These substances include prescription drugs, over-the-counter medications, and veterinary medicines.
Water treatment can reduce some pharmaceutical compounds, but treatment capabilities vary by substance and system. Major health agencies, such as the World Health Organization, describe significant health risks as unlikely based on current exposure levels, though pharmaceuticals remain an area of ongoing research and public interest.
Endocrine-disrupting chemicals (EDCs)
Endocrine-disrupting chemicals can interfere with hormones and may come from plastics, pesticides, personal care products, or industrial processes. Because there are many types and multiple exposure routes, researchers are still working to understand their role in drinking water quality.
What emerging water contaminants mean to you
Water quality has become a mainstream concern, with media coverage of new research findings helping to spark conversations across North America. In some communities, public recognition of potential health risks is turning into action. Residents of Hazelbrook, P.E.I., for example, are suing the government over PFAS contamination in their drinking water.
Navigating federal policy can feel confusing, but knowing what the rules actually mean can clear up a lot of uncertainty. While the EPA established national drinking water limits on “forever chemicals” in 2024, public water systems have years to comply, meaning strict enforcement won’t fully kick in until 2031 or later. Furthermore, recent federal updates mean these rules will focus on the two most common types of PFAS (PFOA and PFOS). Recognizing this long runway doesn’t mean you are powerless — it simply gives you the reality you need to take control of your own home filtration with complete peace of mind.
While broader solutions are underway, you don’t have to sit with the uncertainty of what’s coming out of your tap. Taking a look at your community’s annual water quality report is a simple first step to clearing up any doubts. It’s important to note that your local water provider is not necessarily testing for these emerging contaminants yet, as it is not required, so this should just be a starting point. The best step is to get your water tested, learn about certified water filters, and understand how your local utility treats its supply, which can give you total peace of mind and complete control over what’s in your glass.
How to stay informed as water standards evolve
Advances in testing and monitoring are providing more data than ever before. As scientists learn more about contaminants in drinking water, consumers may see evolving guidelines, new technologies, and greater pressure for transparency from public agencies and water providers.
Understanding what is in your water, following updates from trusted scientific and public health organizations, and knowing which treatment options are designed for specific contaminants can help you make informed decisions as standards continue to evolve.
This story was produced by Culligan and reviewed and distributed by Stacker.